Index: src/natools-s_expressions-printers.adb
==================================================================
--- src/natools-s_expressions-printers.adb
+++ src/natools-s_expressions-printers.adb
@@ -1,7 +1,7 @@
 ------------------------------------------------------------------------------
--- Copyright (c) 2013-2014, Natacha Porté                                   --
+-- Copyright (c) 2013-2015, Natacha Porté                                   --
 --                                                                          --
 -- Permission to use, copy, modify, and distribute this software for any    --
 -- purpose with or without fee is hereby granted, provided that the above   --
 -- copyright notice and this permission notice appear in all copies.        --
 --                                                                          --
@@ -41,10 +41,16 @@
    overriding procedure Close_List (Output : in out Canonical) is
    begin
       Output.Stream.Write ((0 => Encodings.List_End));
    end Close_List;
 
+
+   procedure Append_String (Output : in out Printer'Class; Data : in String) is
+   begin
+      Append_Atom (Output, To_Atom (Data));
+   end Append_String;
+
 
    procedure Transfer
      (Source : in out Descriptor'Class;
       Target : in out Printer'Class;
       Check_Level : in Boolean := False)

Index: src/natools-s_expressions-printers.ads
==================================================================
--- src/natools-s_expressions-printers.ads
+++ src/natools-s_expressions-printers.ads
@@ -1,7 +1,7 @@
 ------------------------------------------------------------------------------
--- Copyright (c) 2013-2014, Natacha Porté                                   --
+-- Copyright (c) 2013-2015, Natacha Porté                                   --
 --                                                                          --
 -- Permission to use, copy, modify, and distribute this software for any    --
 -- purpose with or without fee is hereby granted, provided that the above   --
 -- copyright notice and this permission notice appear in all copies.        --
 --                                                                          --
@@ -37,10 +37,13 @@
 
    procedure Open_List (Output : in out Printer) is abstract;
    procedure Append_Atom (Output : in out Printer; Data : in Atom) is abstract;
    procedure Close_List (Output : in out Printer) is abstract;
 
+
+   procedure Append_String (Output : in out Printer'Class; Data : in String);
+
    procedure Transfer
      (Source : in out Descriptor'Class;
       Target : in out Printer'Class;
       Check_Level : in Boolean := False);